This invention relates generally to pivot joints, and in particular to a pivot joint useful for connecting a headlamp adjuster to a reflector inside a headlamp assembly.
Pivotable spherical joints, commonly referred to as ball joints, include a ball stud engaged in a socket. Such joints have a wide variety of applications where a pivotable connection between two parts is desirable. For example, they may be used in many types of linear actuators and have been found to be particularly useful in automotive lamp assemblies. As disclosed in FIGS. 17 and 23 of U.S. Pat. No. 6,247,868, the disclosure of which is hereby incorporated by reference, automotive lamp assemblies used as headlights typically comprise several basic parts: a support frame, a reflector, a lens, a bulb, and one or more adjusters. The support frame houses the reflector and the bulb on a pivotable mounting to allow the aim of the light to be adjusted using the adjuster. The lens seals the front of the assembly to protect it from the elements assailing the front end of the vehicle and provides an aerodynamic shape and attractive appearance. The reflector mounts inside the housing on a fixed ball joint and is adjustable horizontally and vertically using adjusters that interface with the reflector through moving ball joints. The moving ball joints are moveable by actuating the adjusters connected to the moving ball joints by a ball stud having a head and a shaft. In some automotive lamp assemblies, two fixed ball joints and one moving ball joint may be used.
As is known in the art, ball studs interface with plastic sockets, such as the one shown in FIG. 7. This is just one example of a prior art automobile headlight 10 having a reflective mirror tiltably mounted in a lamp space which is defined by a lamp body 12 and a lens 14. Lamp body 12 is formed of a synthetic resin material and defines a recess 16 which opens in the forward direction. The lens 14 is mounted on the lamp body 12 to cover the recess 16. A reflective mirror 18 is tiltably disposed in a lamp space 20 which is defined between the lamp body 12 and the lens 14.
The reflective mirror 18 is supported on the lamp body 12 at three points. At one point 22 in particular, the reflective mirror 18 is supported on the lamp body 12 through a ball socket assembly 24. Socket assembly 24 comprises a ball stud 26 mounted on the lamp body 12, and a ball socket 28 supported on the reflective mirror 18 by a pair of flexible arms or locking tabs 19. The spherical portion 30 of the ball stud 26 engages with the spherical recess 32 of the ball socket 28, thereby the mirror is pivotably connected to the lamp body 12.
While functionally quite effective, there is at least one shortcoming to using ball studs with locking tabs. This shortcoming is that the locking tabs 19 can be pulled out of reflector wall 21 under certain conditions of operation, leaving the adjuster non-operational. This unexpected pull-out generally occurs because the locking tabs 19 are necessarily flexible. Tabs 19 must be flexible enough to allow the tabs 19 to be inserted into an aperture in the reflector wall 21, while at the same time resist pull-out. Though pull-out of the ball stud is resisted to some degree of success, if enough force is applied, tabs 19 slip inward toward the center of the aperture and the socket 28 xe2x80x9cpops outxe2x80x9d of the wall 21. Reducing the flexibility of tabs 19 has not been found an effective option because it becomes too difficult to insert the socket 28 into the wall 21, or the elasticity of the tabs 19 is lessened to the degree that they break off during insertion of the socket 28.
Accordingly, the need exists for an improved ball socket that can be securely retained in a wall or other structure, can be adapted for use in connection with various ball stud designs, is cost effective, and resists accidental pull-out. The present invention relates to an improved ball joint which is capable of being used in automotive lamp assemblies and solves the problems raised or not solved by existing ball joints. Of course, the present invention may be used in a multitude of non-automotive lamp situations where similar performance capabilities are required.
The present invention provides a ball socket that is cost-effective, easily installed in the lamp where it is securely retained, and is adaptable for use in connection with various ball studs.
The ball socket of the present invention has at least a pair of locking tabs or snap locks extending therefrom. These locking tabs have an outwardly extending lip on the end opposite to where a ball stud is attached to the socket, which creates a necked portion on the locking tabs. The locking tabs elastically deflect inward when inserted into an aperture in a wall or the like, and return to their original position once the locking tab lips are completely through the aperture.
The ball socket further includes a sleeve that is located in the socket cup. When a ball stud is inserted into the socket cup, the sleeve is driven to a location between the locking tabs. This prevents the locking tabs from deflecting inward, and secures the ball socket to the wall or a mounting plate. The sleeve may be connected to the ball socket with by a shear tab that is sheared off by dislocating the sleeve. Alternatively, the sleeve may be separate from the ball socket, and temporarily seated by shear tabs that are also sheared off by dislocating the sleeve.
The ball socket can be designed to accept different types of ball studs, either conventional or disengageable, such as the one disclosed in U.S. Pat. No. 6,113,301. The ability to use the socket with a wide variety of ball studs provides a significant benefit to headlamp assemblers because it allows the use of one style of socket with a number of types of ball stud.
While one possible application of the present invention is in headlamp assemblies, many other applications are possible and references to use in a headlamp assembly should not be deemed to limit the uses of the present invention. The terms xe2x80x9cball stud,xe2x80x9d or xe2x80x9cheadxe2x80x9d as used herein should not be interpreted as being limited to spherical or semispherical shapes, rather, the heads of ball studs in accordance with the present invention may have a wide variety of shapes and may include protrusions having semispherical or otherwise pivotably-shaped tips. These and other objects and advantages of the present invention will become apparent from the detailed description, claims, and accompanying drawings.